Sensor assembly for detecting position of target surface based on a reference portion of target surface and method

ABSTRACT

A sensor assembly includes a first structure and a second structure disposed radially outwardly of the first structure. Also included is a sensor body extending through the first and second structures, the sensor body having first and second ends, the first end disposed proximate a first environment and the second end located radially outwardly of the second structure. Further included is a first sealing assembly configured to operatively couple the sensor body to the second structure and to accommodate movement of the sensor body. Yet further included is a position sensor operatively coupled to the sensor body, the position sensor configured to determine a position of a target. Also included is a target surface having a reference portion and an inclined portion located adjacent the reference portion, wherein the position sensor is configured to detect the position of the target based on a distance differential.

FEDERAL RESEARCH STATEMENT

The invention disclosed herein was made with Government support underContract No. N00014-09-D-0821 with the United States Navy. TheGovernment may have certain rights in the subject matter disclosedherein.

BACKGROUND OF THE INVENTION

The embodiments herein generally relate to sensor assemblies and, moreparticularly, to a sensor assembly extending through a plurality ofstructures which separate distinct operating environments, as well as amethod of detecting position of a target through multiple structures.

Adjustable guide vanes within compressor sections of a turbine engineare known and are able to be monitored with sensing equipment. Sensingequipment in a turbine section of a gas turbine engine poses morechallenges due to a high temperature and pressure environment therein.Typically, a hot gas path of a turbine section is surrounded by multiplelayers of structures that are subjected to distinct thermal growthcycles due to the distinct environments defined by each structure.Challenges with sensing include operating in extreme hot pressurizedenvironments and bringing the signal out to the outer surface of theengine through multiple engine sections. The distinct thermal growthrates noted above are combined with tolerance stacking of the varioushardware pieces.

BRIEF DESCRIPTION OF THE INVENTION

According to one embodiment, a sensor assembly includes a firststructure defining a first interior volume having a first environmentwith a first temperature and a first pressure. Also included is a secondstructure disposed radially outwardly of the first structure anddefining a second interior volume having a second environment with asecond temperature and a second pressure each lower than the firsttemperature and the first pressure. Further included is a sensor bodyextending through the first structure and the second structure, thesensor body having a first end and a second end, the first end disposedproximate the first environment and the second end located radiallyoutwardly of the second structure. Yet further included is a firstsealing assembly configured to operatively couple the sensor body to thesecond structure and to accommodate movement of the sensor body due torelative movement between the first structure and the second structure.Also included is a position sensor operatively coupled to the sensorbody, the position sensor configured to determine a position of a targetlocated within the first interior volume. Further included is a targetsurface of the target, the target surface having a reference portion andan inclined portion located adjacent the reference portion, wherein theposition sensor is configured to detect the position of the target basedon a distance differential between the distance from the sensor to thereference portion and the distance from the sensor to the inclinedportion.

According to another embodiment, a method of detecting an angularposition of a target through multiple structures separating multipledistinct environments. The method includes penetrating a plurality ofstructures with a sensor body, a first end of the sensor body beingdisposed within a first interior volume having a first environment witha first temperature and a first pressure, a second end of the sensorbody being disposed in environment having a temperature and a pressureeach lower than the first temperature and the first pressure, the secondend having a sensor mounted thereto. The method also includes detectinga first distance from the sensor to a reference portion of a targetsurface of the target, wherein the target is disposed within the firstinterior volume. The method further includes detecting a second distancefrom the sensor to an inclined portion of the target surface, whereinthe inclined portion varies as a function of rotational position of thetarget. The method yet further includes calculating the differencebetween the first distance and the second distance surface of the targetto obtain the angular position of the target.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter which is regarded as the invention is particularlypointed out and distinctly claimed in the claims at the conclusion ofthe specification. The foregoing and other features and advantages ofthe invention are apparent from the following detailed description takenin conjunction with the accompanying drawings in which:

FIG. 1 is a perspective view of a portion of a turbine section having aplurality of structures separating a plurality of volumes havingdistinct operating environments;

FIG. 2 is a partial cross-sectional view of a sensor assembly extendingthrough the plurality of structures of the turbine section for detectionof multiple portions of a target surface of a target for detection ofangular position of the target;

FIG. 3 is an enlarged perspective view of the target surface; and

FIG. 4 is a top plan schematic view of the target surface.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, a portion of a turbine section is illustrated andgenerally referenced with numeral 10. In an exemplary embodiment, theturbine section 10 is part of an aircraft engine, such as a highpressure turbine or a low pressure turbine. Illustrated is a portion ofa single stage of the turbine section 10. Included is a plurality ofadjustable vanes 12, such as adjustable stator vanes and which may bereferred to interchangeably, that are configured to rotate in acontrollable manner. The number of vanes within a single stage may varydepending upon the application. In one embodiment, the number ofadjustable vanes varies from about 20 vanes to about 40 vanes. Rotationof the adjustable vanes 12 is desirable due to increased efficiency andperformance of the aircraft engine. Specifically, the adjustable vanes12 may be rotated to optimal angles corresponding to different operatingconditions of the aircraft engine. For example, improvements in specificfuel consumption are seen by adjusting the vanes based on certainoperating conditions. Segments of the guide vanes 12 are typicallyrotated concurrently by a linkage mechanism or the like that includes acrank arm or other mechanical structure operatively coupled to the guidevanes 12. It is to be appreciated that all or only some of the totalnumber of vanes within a stage may be rotatable. For example, in someembodiments, only half of the total vanes are rotatable. In such anembodiment, every other vane may be rotated. As one can understand, anyfraction of the total number of vanes may be rotated and the spacingbetween the vanes that are adjustable may vary. Numerous contemplatedcombinations may be suitable for different embodiments.

The adjustable vanes 12 are disposed within a first interior volume 14having a harsh operating environment (also referred to herein as a firstenvironment) where a hot gas passes over them in an effort to convertthe thermal energy of the hot gas to mechanical work for propulsion ofthe aircraft. The first interior volume 14 is defined by a firststructure 16, such as a turbine casing, and the first environment has afirst temperature and a first pressure. The precise temperature andpressure will vary depending upon the type of aircraft engine and theoperating conditions, but reference to the first temperature and thefirst pressure will be appreciated based on their values relative toother environments of other volumes discussed herein. Disposed radiallyoutwardly of the first structure 16 is a second structure 18, such as aninner casing. An inner surface of the second structure 18 and an outersurface of the first structure 16 define a second interior volume 20.The second interior volume 20 has a second environment therein, with thesecond environment having a second temperature and a second pressure.The precise temperature and pressure of the second environment will varydepending upon the type of aircraft engine and the operating conditions,but irrespective of those variables, the second temperature and thesecond pressure are lower than the first temperature and the firstpressure, respectively. Disposed radially outwardly of the secondstructure 18 is a third structure 22, such as an outer casing. An innersurface of the third structure 22 and an outer surface of the secondstructure 18 define a third interior volume 24. The third interiorvolume 24 has a third environment therein, with the third environmenthaving a third temperature and a third pressure. The precise temperatureand pressure of the third environment will vary depending upon the typeof aircraft engine and the operating conditions, but irrespective ofthose variables, the third temperature and the third pressure are lowerthan the second temperature and the second pressure, respectively. Anambient environment 23 is located radially outwardly of the thirdstructure 22. The ambient environment 23 has an ambient temperature andan ambient pressure that are lower than the third temperature and thethird pressure, respectively. It is to be understood that more or lessstructures, and therefore volumes with different environments, may bepresent. The embodiments described herein benefit multi-layer structureswith different environments, as will be appreciated from the descriptionbelow.

Although the structures, volumes and environments described above andillustrated are in the context of an aircraft engine, it is to beappreciated that any structure requiring separation of multiple volumesthat are subjected to distinct environments will benefit from theembodiments described herein.

Referring now to FIG. 2, with continued reference to FIG. 1, a sensorassembly 30 configured to penetrate multiple structures is illustratedin detail. The sensor assembly 30 may be used in conjunction with anystructure or assembly that has a plurality (i.e., two or more) ofstructures that define multiple distinct environments. The sensorassembly 30 is operatively coupled to each of the plurality ofstructures and includes features that accommodate relative movementbetween the plurality of structures that occurs due to the distinctoperating environments.

In the illustrated exemplary embodiment of FIG. 1, the sensor assembly30 penetrates structures of the turbine section 10 and is subjected tothe distinct environments that are defined by those structures. Inparticular, the sensor assembly 30 includes a sensor body 32 thatpenetrates through apertures of at least two structures, such as a firstaperture of the first structure 16, a second aperture of the secondstructure 18 and a third aperture of the third structure 22. It is to beappreciated that the sensor body 32 may penetrate only two structuresand may penetrate more than the three illustrated structures as well,depending upon the particular structure or assembly that the sensorassembly 30 is employed with. The sensor body 32 extends from a firstend 34 to a second end 36. The first end 34 is disposed radiallyinwardly proximate the first structure 16 and is operatively coupledthereto. Coupling of the first end 34 of the sensor body 32 to the firststructure 16 may be facilitated in any known securing process, such aswelding, mechanical fasteners or threaded connection. The first end 34may protrude slightly into the first interior volume 14, such that it isexposed to the first environment.

In one embodiment, a sensor 42 is located proximate the second end 36. Asignal is routed along an interior cavity 38 of the sensor body 32 thatis defined by an interior wall 40 of the sensor body 32. The interiorcavity 38 may be formed of any suitable geometry, such as cylindrical,for example. The interior cavity 38 provides a protected path for thesensor signal to be routed from the first end 34, where sensingdetection is made, to the second end 36 where the sensor 42 isoperatively coupled. The sensor 42 may be coupled to the sensor body 32proximate the second end 36 in any suitable manner. The second end 36 isdisposed outside of the first interior volume 14. In the exemplaryembodiment, the second end 36 of the sensor body 32, and therefore thesensor 42, is located in the ambient environment 23 radially outwardlyof the third structure 22, but placement of the sensor 42 in one of themore benign environments (e.g., second interior volume 20 or thirdinterior volume 24) is contemplated. Placing the sensor 42 in a locationoutside of the harsh environment of the first interior volume 14, andpossibly outside of the second and third interior volumes 20, 24, allowsfor a wider selection of sensors. Wider selection is available based oncertain sensors having sensitive limitations on the operatingenvironments in which they may be disposed.

The sensor 42 is connected to the sensor instrumentation (not shown)that is housed within a less harsh environment. The sensorinstrumentation is configured to detect at least one characteristic of atarget 13, such as the adjustable stator vanes 12 disposed within thefirst interior volume 14. The terms target and adjustable stator vanes12 may be used interchangeably herein as the target 13 and the vane maybe a, single integrally formed structure or may be distinct componentsthat are operatively coupled to each other in a fixed manner, such thatrotation of the vane imparts corresponding rotation of the target. “Atleast one characteristic” refers to any characteristic that is commonlymeasured by sensors. For example, position of the target, temperature ofthe target and pressure proximate the target are all examples ofcharacteristics that may be detected by the sensor 42. In an exemplaryembodiment, the sensor 42 is configured to detect an angular position ofthe adjustable stator vane 12 via signals generated from the target 13located proximate the first end 34 of the sensor body 32 and that isoperatively coupled to the adjustable stator vane 12. The interactionbetween the sensor instrumentation and the target 13 will be describedin detail below.

In another embodiment, a sensor 100 (shown schematically in phantom inFIG. 2) may be located proximate the first end 34 of the sensor body 32in a coupled manner. Some sensors are able to withstand more stressfuloperating environments and may be suitable for use in such a location.The sensor 100 includes a sensor face 102 that is located in closeproximity to the target 13 and the interaction between the sensor face102 and the target 13 will be described in detail below.

Remotely locating the sensor 42 in a less harsh environment, such as theambient environment 23, ensures accurate and reliable operation of thesensor 42, thereby providing more accurate measurements, but asdescribed above it is contemplated that a suitable sensor 100 is locatedproximate the harsh environment. Either way, relative movement of theplurality of structures that the sensor assembly 30 penetrates and isoperatively coupled to leads to potential detrimental effects related toaccuracy and reliability of the measurements. The relative movement isattributed to effects of the distinct operating environments, such asdifferent thermal growth rates of the structures. The relative movementof the structures, 16, 18, 22, may be in the radial, axial and/orcircumferential direction.

To accommodate the relative movement of the structures, one or moresealing assemblies are provided to operatively couple the sensor body 32to respective structure(s). The number of sealing assemblies will dependupon the number of structures to which the sensor body 32 is topenetrate and to be operatively coupled to. In the illustratedembodiment, operative coupling of the sensor body 32 to the firststructure 16 is made by a mechanical process, such as a threadedconnection, as described in detail above. The sensor body 32 isoperatively coupled to the second structure 18 with a first sealingassembly 50.

The first sealing assembly 50 includes a radial seal 52 that is disposedin a groove 54 of the sensor body 32. The groove 54 extendscircumferentially around an outer surface 56 of the sensor body 32 in aradial location proximate that is at the radial location of the secondstructure 18. The groove 54 extends completely around the sensor body32. The radial seal 52 is configured to be at least partially disposedwithin the groove 54 and is in abutment with a radial seal backer 58that is sandwiched between the radial seal 52 and a radial seal retainer60. The radial seal retainer 60 is disposed in a notch 62 of the sensorbody 32. As with the radial seal 52, the radial seal backer 58 and theradial seal retainer 60 each extend completely around the sensor body32. The abutment of the radial seal retainer 60 and the radial sealbacker 58, in combination with the abutment of the radial seal backer 58and the radial seal 52, biases the radial seal 52 to fix the radial seal52 in a radial direction. The radial seal retainer 60 is typically asubstantially rigid structure, such that stiff support of the radialseal 52 is achieved. The radial seal 52 is at least partially flexiblein order to accommodate relative movement of the structures in a radialdirection, thereby allowing the sensor body 32 to move slightly in theradial direction, while maintaining a sealed arrangement.

The first sealing assembly 50 also includes a slider plate 64. Theslider plate 64 is a single, integrally formed structure that includes acylindrical portion 68 and a ring portion 70. The cylindrical portion 68extends circumferentially around the sensor body 32 and, moreparticularly, around the radial seal 52. The cylindrical portion 68 isin abutment with the radial seal 52 to fix the radial seal 52 in axialand circumferential directions. The ring portion 70 is orientedsubstantially perpendicularly to the cylindrical portion 68 and isdisposed in contact with a radially inner surface of a mounting body 90that is coupled to the second structure 18. As shown in the illustratedembodiment, the mounting body 90 may be a ring-like structure thatdirectly mounts to the second structure 18 via mechanical fasteners 92,however, alternative geometries and coupling processes may be employed.The mounting body 90 may be a single ring that extends circumferentiallyaround the entire sensor body 32 or may be segmented. A slider plateretainer 72 is disposed within a recess 74 of the mounting body 90 andis in abutment with the slider plate 64 to fix the slider plate in aradial direction. The slider plate retainer 72 is typically asubstantially rigid structure, such that stiff support of the sliderplate 64 is achieved. The slider plate 64 is at least partially flexiblein order to accommodate relative movement of the structures in both thecircumferential and axial directions, thereby allowing the sensor body32 to move slightly in these directions, while maintaining a sealedarrangement.

As described in detail above, additional structures, such as the thirdstructure 22 may require penetration and operative coupling by thesensor assembly 30. In such embodiments, additional sealing assembliesidentical to that described above in conjunction with the first sealingassembly 50 are employed. For example, a second sealing assembly 80 isillustrated. The second sealing assembly 80 includes identical sealingcomponents to accommodate relative movement of the first, second andthird structures 16, 18, 22. Such components are illustrated and labeledwith corresponding numerals associated with the sealing components ofthe first sealing assembly 50. For purposes of description, additionalsealing structures are not described or illustrated, but it is to beappreciated that additional sealing assemblies may be included to coupleto additional structures.

As described above, the sensor 42 may be distanced from the harshenvironment of the first interior volume or may be the sensor 100described above that is located proximate such an environment.Regardless of the precise location of the sensor, 42 or 100, the sensorinstrumentation or sensor face 102 is located in close proximity to thetarget 13. More particularly, an end of the sensor face 102 can belocated in close proximity to a target surface 104 of the target 13. Thetarget surface 104 includes two distinct portions that are locatedadjacent to each other. A reference portion 106 is included and has ageometry that does not vary as a function of rotation of the target 13.For example, the reference portion 106 may be a substantially flatsurface or a slightly arcuate surface. An inclined portion 108 may be inthe form of any geometry that is not aligned in a parallel manner withthe reference portion 106. Specifically, in the illustrated embodiment,the inclined portion 108 is an inclined plane that extends around atleast a portion of the radially outer surface of the target 13 andadjacent the reference portion 106. Although described above andillustrated as an inclined planar surface, it is to be appreciated thatother contoured surfaces, such as non-planar geometries may be employed.

The sensor face 102 is configured to process a specific signal based ondistances between the sensor face 102 and the reference portion 106, aswell as between the sensor face 102 and the inclined portion 108. Forexample, a first signal is generated and obtained based on a firstdistance defined by the distance between the sensor and the referenceportion 106, while a second signal is generated and obtained based on asecond distance defined by the distance between the sensor and theinclined portion 108.

As the target 13 is rotated, the distance detected by the sensor 42, 100will vary due to the inclined portion 108. However, due to thermalinduced changes to the components and assemblies, the relative distancebetween the sensor and the inclined portion 108 may vary duringoperation for reasons other than rotation of the target 13. To accountfor such changes, the reference portion 106 is provided to constantlyprovide a reference distance to compare the second distance (i.e.,sensor to inclined portion 108) to. The reference portion 106 moves withthe inclined portion 108 as a consequence of being located on the samecomponent in an adjacent manner and that is subjected to the samethermal changes, thereby providing a grounding, or reference, pointwhich is a constant plane that does not vary with rotationaldisplacement of the target 13.

The two distances detected are obtained and a distance differential isdetermined. The distance differential is correlated to a unique angularposition of the target 13. The correlation may be made by comparing thedifferential to stored values relating to angular positions.Alternatively, the differential may be input into calculations todetermine the angular position. Irrespective of the precise manner inwhich the differential is employed, each distance differentialcorresponds to a unique angular position of the target 13, and hence theadjustable stator vane 12.

Advantageously, the embodiments described herein allow for penetrationthrough multiple temperature and pressure environments in order tomonitor signals deep within a harsh operating environment, such as a hotgas path of a turbine engine. Furthermore, the embodiments achieveaccurate positional sensing and detection of a target, such as theadjustable stator vane described herein. Additionally, detection of theangular position with the reference portion 106 provides a friction freesystem of measurement as there are no contacting surfaces to affect themechanical movement of the system. Other benefits include the provisionof greater selection of the sensing technology that is best suited tomeet performance requirements.

While the invention has been described in detail in connection with onlya limited number of embodiments, it should be readily understood thatthe invention is not limited to such disclosed embodiments. Rather, theinvention can be modified to incorporate any number of variations,alterations, substitutions or equivalent arrangements not heretoforedescribed, but which are commensurate with the spirit and scope of theinvention. Additionally, while various embodiments of the invention havebeen described, it is to be understood that aspects of the invention mayinclude only some of the described embodiments. Accordingly, theinvention is not to be seen as limited by the foregoing description, butis only limited by the scope of the appended claims.

What is claimed is:
 1. A sensor assembly comprising: a first structuredefining a first interior volume having a first environment with a firsttemperature and a first pressure; a second structure disposed radiallyoutwardly of the first structure and defining a second interior volumehaving a second environment with a second temperature and a secondpressure each lower than the first temperature and the first pressure; asensor body extending through the first structure and the secondstructure, the sensor body having a first end and a second end, thefirst end disposed proximate the first environment and the second endlocated radially outwardly of the second structure; a first sealingassembly configured to operatively couple the sensor body to the secondstructure and to accommodate movement of the sensor body due to relativemovement between the first structure and the second structure; aposition sensor operatively coupled to the sensor body, the positionsensor configured to determine a position of a target located within thefirst interior volume; and a target surface of the target, the targetsurface having a reference portion and an inclined portion locatedadjacent the reference portion, wherein the position sensor isconfigured to detect the position of the target based on a distancedifferential between a first distance from the sensor to the referenceportion and a second distance from the sensor to the inclined portion.2. The sensor assembly of claim 1, wherein the position sensor iscoupled to the sensor body proximate the first end of the sensor body.3. The sensor assembly of claim 1, wherein the position sensor iscoupled to the sensor body proximate the second end of the sensor body.4. The sensor assembly of claim 1, wherein the reference portion of thetarget surface comprises a flat surface.
 5. The sensor assembly of claim1, wherein the reference portion of the target surface comprises anarcuate surface.
 6. The sensor assembly of claim 1, wherein the inclinedportion of the target surface varies with rotational displacement of thetarget.
 7. The sensor assembly of claim 1, wherein the position sensorobtains a first signal based on the first distance and a second signalbased on the second distance.
 8. The sensor assembly of claim 1, whereinthe distance differential detected by the sensor corresponds to a uniqueangular position of the target.
 9. The sensor assembly of claim 1,wherein the sensor assembly is disposed in a turbine section of anaircraft engine.
 10. The sensor assembly of claim 9, wherein the targetis operatively coupled to an adjustable vane of the turbine section. 11.The sensor assembly of claim 9, wherein the first structure comprises aturbine casing, the second structure comprises an inner casing and thethird structure comprises an outer casing.
 12. A method of detecting anangular position of a target through multiple structures separatingmultiple distinct environments, the method comprising: penetrating aplurality of structures with a sensor body, a first end of the sensorbody being disposed within a first interior volume having a firstenvironment with a first temperature and a first pressure, a second endof the sensor body being disposed in environment having a temperatureand a pressure each lower than the first temperature and the firstpressure, the second end having a sensor mounted thereto; detecting afirst distance from the sensor to a reference portion of a targetsurface of the target, wherein the target is disposed within the firstinterior volume; detecting a second distance from the sensor to aninclined portion of the target surface, wherein the inclined portionvaries as a function of rotational position of the target; andcalculating the difference between the first distance and the seconddistance surface of the target to obtain the angular position of thetarget.
 13. The method of claim 12, wherein obtaining the angularposition of the target based on the calculated difference comprisescorrelating the difference to a plurality of stored correspondingangular positions of the target.
 14. The method of claim 12, whereinobtaining the angular position of the target based on the calculateddifference comprises calculating the angular position based on thedifference.